Machine for ramming molds



Aug- 27 1940 M. G. CLAY ET AL MACHINE Fon RAMMING MoLDs 5 Sheets-Sheet l Filed Nov. l5, 1957 J7 7712er O,

Allg- 27, 1940- M. G. CLAY ET Al.

MACHINE FOR RAMMING MOLDS Filed Nov. l5, 1937 3 Sheets-Sheet 2 Aug- 27, 1940- M. G. CLAY ET A1. 2,212,510

MACHINE FOR RAMMING MOLDS Filed NOV. l5, 1937 3 SheeLs-Shee1'l 3 .iiilutin Patented Aug. 27, 1940 MACHINE FOR RAMMING -MOLDS' vMurray G. Clay and Elmer 0. BeardslemChicago, i l Ill.assignors to Thev Beardsley & Piper Coml pany, Chicago, Ill., a corporation oitIllinois,` l f f Application November 15,1937, serial-N0. 174,633 n 16 claims. (c1. 2.2-2.6) `4 The invention relates to controlling-meansfor power-operated mechanism for moving sandprojectors over flasks.

In the use of sand-projectors which are movable over flasks of great area, the jointed structure comprising `supportirig-arms must be/of great length, for ramming all portions of the fiasks' and this makes it difiicult for an operator i tomanually move the projector and supportingstructure. A desideratum is to use projectors with suiiicientcapacity for throwing large quan- `titiesof sand which requires heavy projectors and y supports. This heavy apparatus requires such great manual force in moving the projector over the flask that the operators can not endure the strain of the Work.` l l vOne object of the invention is to provid-e manually-operable controlling-means yfor poweroperated mechanism for Shifting the jointed lsupporting-structure for the projector whereby the f operator may easily control the horizontalY movementlof the projector in any direction over fiasks of great area, responsively to manual movement of acontrol-device corresponding to the desired direction and extent of the projector.

Another object of the invention is to provide manual controlling-means which comprises a plurality of arms pvoted together and controlling-means for power-mechanism whereby a supporting structure comprising a pair of pivotally-supported arms, may be shifted f correspondingly to the controller-arms, so that the operator can control the direction and lextentof movement of the power-shifted supporting-arms by similar movements of the controller-arms.

Another-object of the invention is to provide electrical control-means for power-operated mechanism for shifting the projector horizontally in any direction over flasks.

Other objects of the invention will appear from the detailed description.

The invention consists in the several novel features hereinafter set forth and more particularly dened by claims at the conclusion hereof.

In the drawings: Fig. l is a side elevation of a sandslinger embodying the invention, parts being shown inv section. Fig. 2 is a diagram of the electrical apparatus and connections for controlling the movements of the supporting-arms by power.' Fig. 3 isa vertical section of the manually-shiftable device ior'controlling the powerloperated mechanism for shifting the supportingarms. Fig. 4 is aflongitudinal section through the pivotal supporting-connection between the lstationarystandard and the -rst horizontally- `the cushioning device between the rst support- PATENT j swinging rsupporting-arm. Fig. 5 is a section of Y the pivotalsupporting-connection between the pivo-tally-connected isupportingfarms.lk Fig. 6 'is' a detail .Section on line 4-4 `of'l'ig. 4 Showing ing-arm Tand ther power-driven mechanism for swinging it. Fig; 7 I'is a section online 5--5 of Fig. 5 illustrating the cushioning devicebetween the second supporting-arm and the power-operated shifting -mechanism for swinging it.

The vinvention is exemplified` in apparatus for slinging sandinto flasks by means of a vrotary projector which comprisesV a casing l!) Vand a rotary blade Il, whichv is fixed to, and driven at a high speed by, theshaft of an `electric motor I2?, whchis supported so as to be horizontally movable with the projector. Theprojector is supported for universal horizontal movement o-ver flasks' to deliver wads of sand at high speed intoy all portions of large flasks by a jointed structure which comprises a pair of armsA, B. Arm Ais pivotally supportedfor horizontal movement on a stationary standard i4 and arm-B is pivotally supported for horizontal movement on the -distal end of arm A, so that eitherof the arms may be movedtoshift the projector, or their horizontal swinging movements maybe compounded to bring' the projector over 'all Vparts of the flask. Arm B is tubular and `projector-casing l0 is Xed to the outer end ofsaid arm. Electric motor l2, which drives the projector, is mounted `adjacent the inner end ofarmB.- A sleeve 65,

supported` by roller-bearings Glen stationary standard i4, is fixed to the inner end of arm. A to support said arm 'for' i vhorizontal swinginlg movement on said standard.` Standard lil is secured on the topV of a stationary housing Al'l.

bracket 'i3 which is yxed to the housing of moto-r I 2. A spindle l2 is fixed to, and depends from,

bracket 13, for pivotally connecting the inner end of arm B- and the outer end of arm A Vfor horizontal relative swinging movement of lthe arms. Spindlef'lZ is carried in a bracket or housing 92 which is fixed tothe outerend of tubular arm A. l i w Y The machine is equipped with means for feeding sand tothe projector, such, :for exampleas a vibratory chute K, which contains a screen. Said chuteis vibrated by an eccentric pineal@ which is driven by reduction-gearing 7c. An electric motor lc .drives gearing lc. This gearing and motor are mounted on a bracket 91 which is xed to the top of sleeve 66 so they will swing horizontally with arm`A. One end of chute K is supported by a resilient strip 7c3.

' thus supported, swings horizontally with supportsupported by eccentric-pin k2, which is supported by the gearing k, andits other end is The chute, as

ing arm A. lChute K delivers the sand into a hopper I from which it falls onto anendless belt L, which is driven through suitable gearing (not shown) by motor'l2, which drives the projector.

This belt delivers the sand into the projectorcasing. Hopper l and belt L are supported on,' and to swing with, the supporting-arm B. This sand-feeding mechanism is adapted to continuously feed sand to the projector in `all positions of the supporting-arms.

The .invention provides for horizontally `swinging supporting-arms A and B by power, in orderY to relieve the operator of the heavy work of moving the projector over the flasks and swinging the Supporting-*arms A, B. A reversible electric motor A is provided for swinging the supporting-armA in opposite directions around standard Hl, anda reversible electric motor B islprovided for swinging supporting-arm B horizontally in :opposite directio-ns relatively to the` supportingfso Aarm A. Motor 'A'v is-connected to drive speedreductionl gearing 14, which is'mounted in a housing l5, Whichisiixed to, and supported by,

the stationary housing I3. Motor A is supported from gear-housing 15. This gearing 14 drives a sprocket-wheel 1,1 to rotate arm A through a sprocket-chain 18 and a sprocket-wheel 18 which isfconnected by bolts 8l) to the sleeve B6 which4 is fixed to arm' A. For the purpose of cushion- `fing the movements of arm A in its movement by power, the power from sprocket 19 is applied to arm A through a pair of rubber cushions 82. rIhe linner ends oficushions 82 are provided with plates 83 for engaging the opposite sides of arm A and their outer ends are carried in a U-shaped `bracket 84 which is xed to, and rotates with power-driven sprocket-wheel 19; Bolts 80 pass Ythrough slots' 8| in sprockets 19 to provide a floose connection between said sprocket and the sleeve 86 which is fixed to, and swings positively with, arm A, so that the initial swinging movemotor A is stopped in controlling the movement of said arm A.

Motor B', which is provided for swinging arm 'B by power, is connected Vto swing said arm through speed-reduction gearing 85in a casing 86 to which the casing of motor B is secured. Casing is fixed to bracket 92 which swings with 'arm A. Gearing 85.comprises .a bevel-gear 8l xed to a shaft 88 which Vis journaled in casing 86, a bevel-pinion 89, xed to said shaft, and a bevel-gear il!)y which is fixed to a sleeve 9i which `is journaled in ra bracket y92. Sleeve 9| is driven by power from motor B', to swing arm B through a forked'bracket 93 which is xed to the sleeve 9| and carries rubber cushions 94 with -plates 95 for engaging arm B. This provides a 'cushioned driving-connection between sleeve 9| .and arm B. Spindlei12 rotates in sleeve 9| so Aarm B will be shifted by said cushions 94.

Theinvention comprises a unitary manuallyzshiftable controlling-device for motors A', B', for swinging supporting-arms A, B to move the projector horizontally in any `direction and varying distances over the iiask. This controlling-device comprises a controller-arm a which controls the operation ofvmotor A' for swinging supportingarm A and a controller-arm b which is pivoted to the distal end of controller-arm a and controls the swinging movement of supporting-arm B by motor B. This controlling-device is manually shiftable by the operator to control mechanismwhich controls theoperation of motors A, B to move arms A, B, responsively, in direction and extent, to the movements of the controller-arms a, b. These controller-arms a, b are separately and simultaneously movable to ycause separate or compound swinging movements of supporting-arms A, B and automatically control motors A', B responsively to corresponding movements of the controller-arms.

This controlling-device and a seat M for the operator are preferably supported so they will move with the supporting-arm B which carries the projector. By mounting the operators seat above the projector and on the supporting-arm B, he will be moved with the projector and can observe the delivery of the sand into all portions vof the flask so that he can control the horizontal movement of the projector to uniformly ram all portionsoi the iiask with sand. Seat M is supported on a tubular bracket lill which is fixed to supporting-arm B and a foot-rest E82 for the operator is iixed to said bracket. Controller-arm a is pivotally mounted to swing around a vertical stud H33 which is iixedly supported in a bracket E88 which is clamped to bracket lill in front of,

and adjacent to, the operators seat. Controllerarm bis pivoted on a stud |84 carried by the distal end of arm a. and its handle b is within convenient reach of the operator. n

The means for controlling'the operation'of reversible motor A to swing supporting-arm A ,responsively to the movements of rcontroller-arm a, comprises,v an alternating current potentiometer which is mounted under controller-arm a and includes a laminated circular core composed of thin washers of transformer grade silicon steel, hereinafter referred to as a circular ring c with a toroidal winding and a rotatable contactor ,e which is fixed to swing with said controller-arm a, and an alternating current potentiometer which is mounted in housing i3 and includes a stationary circular core with a toroidal winding,

hereinafter referred toas ring C, and a contacter E which is rotatable directly with sprocket 79. Contactor E is iixedly secured `to the lower end of a hollow shaft 9G which extends upwardly from housing i3 through standard i4 and is secured to rotate with sprocket 'I9 so that said contactyarm will rotate with supporting-arm A except ,ends of the winding on alternating current potentiometer-core c are connected` to power-supply line-conductors'l 38 and 3l through conductors c', 38a, and conductors c2, Sia, respectively. Alternating current potentiometer-rings C and c have their corresponding terminals connected across one phase of the power-supply line, and are ener- `gized at all times in equal phase and voltage in such manner thatV corresponding points on each of the two alternating current potentiometerrings have exactly equal potentials.

Potentiometer-ring c of the controlling-device ,which comprises a sprocket-wheel |05, which is xedly supported on a bracket `|06 coaxially with the` axis of standard I`l|-` and arm Afand a Vsprocket-chain |01; which extends around fixed sprocket |05 and around a sprocket |08 to which is -xed the potentiometer-ring c under controller-arm a. This sprocket-wheel and chain connection, while supporting-arm A is shifted by l power, maintains the same relative angular position between potentiometer-rings C, c in all angular positions of supporting-arm A. Contactor e is fixed to controller-arm a androtates around ring c when said arm a,r is swung in either direction relatively to said ring c correspondingly to the direction and extent of movementof .said arm a around stud |03. i t

'The means for controlling the operation of motor A includes an alternating current polar relay G which comprises aL helix 63 around armature 62 and connected `by conductor e to co-ntactors E, c, field-windings 60, 6|, and a magnet m for holding the armature in its centralized position. Field-windings 6|' and 60 are energized through conductors 31, 38, `transformer windings J, J', and conductors e4, e5 from the same phase of power-supply as the windings of alternating current potentiometer-rings C, c.

Armature `62 is movable in opposite directions from its centralized position to shift either of a pair of switches 64, 65, which control a relay G,

which controls circuitsfor operating motor A' iny tact 6'I, when `armature 62` is shifted in the opposite direction, to control. a `circuit through' winding@` which operates a vswitch g2 which carries contacts 53, 54, 55 for closing athree-'phase circuit through motor A 'for driving the motor in the reverse direction and correspondingly `shifting the supporting-arm A. When arms a and A and, correspondingly, contacts e and E are in the same relative angular positions, no difference of potential will exist between contacters e and E, and no current will flow` through the connecting circuit e, e1, 63, e1, 33, E. 'Ihepivoted armature 62 will then be equally attracted to each of the pole pieces energized by field-windings 6| and 60, so that armature 62 remains in its centered position by the attraction of permanent magnet m.

When controller-arm a is rotated clockwise in relation to ring c, contact ewill vary its angular position relatively `to contact E, so that a difference of potential will exist between thesetwo points, causing `current to iiow through the circuit; contacter e, conductor e and winding 63, `lamp 33 and contacter E. Depending upon the relation of the phases between held-windings 60, 6| and armature-winding 63armature 62 `will be attracted by 'one pole-piece and repelled by the other, moving armature,` 62,to Vclose switch 64 at `t6. Current will now flow from the powersupply conductor 30 through switch 66v and contact 64 through power-relay winding g4 to powerisupply conductor 3|, attracting armature y', closing main power-contacts 50, 5| and 52, andv ener- .gizing motor A. These connections are so related that' motor A is arranged to rotate arm A in such direction as to restore the equality of potential -between contacts e and E.` As soon as this equalityV of potential is established, winding 63 is no` long-er energized and centering-magnet m restores armature 62 toits center position to open switch 64` at* contact |56,` de-energizingpower-relay wind- .ingxg `allowing `armature g to drop, and open contacts 50, 5|' and 52 and stop motor A'.

When arm a is rotated in a counter-clockwise ldirection from rva position in which arm a, and arm A are. in the same positions relatively to alter- `nating current potentiometer-rings c andl C, respectively, a diierence of potential is again established between contacts e and E so that currentlwill ow through the, circuit including contacter e, conductor e and winding 63, lamp 33 and contacter E. At this pointk the phase relation between the current flowing through armature-winding 63 and the current iiowing through field-windings 60 and 6| is exactly opposite from the relation between these two currents which existed in the previous case in which arm a was rotated in a clockwise direction in relation to arm A, so that yarmature 62 willrbe attracted in the `correct direction to closeswitch 65 at contact'l, .thus permitting current to ilow from the power- 61, conductor 39, and power-relaywinding g3 to power supply conductor 3 I attracting armature g2,

closing power-supply contacts 53, 54, 55r thus energizing motor A. The closing of contacts 53, 5II, Y55 interchanges the connection of power-sup- ,ply conductors 30 and 32 in relation to the connections which existed when contacts 50, 5I and 52 were closed, causing themotor to rotate in the opposite direction to rotate arm A in such direction as to restore the equality of potential between contacts e and E. n

This exemplies control-mechanism for the motor A for swinging` arm A responsively to the 'manual shift'of the controller-arm` a, whereby the supporting-arm will `be shifted, in direction and extent, to correspond withthe movement of said controller-arm by the operator. It also exemplifies mechanism controlled by said manually-shiftable controller-arm, in which a differential in vvoltage and reversal of polarity of current through a polarrelay, are utilized to automatically control the swinging movements of the lsupporting-arm by the motor. Y

The vertical axis of stud I03on which sprocket |08, ring e, and controller-arm a, are pivoted, is coaxial with the pivot between supporting-arms A and B, so that the control-device will move laterally with supporting-armA and the axis of arm a. ofthe control-device will remain coaxial with the pivot between the supporting-arms A, B during all' of the swinging movements` with the arm A.

`The -means controlled by 'the movements of controller-arm b for controlling the operations of reversible motor B for swinging supporting- .arm B, comprises'an alternating current potenreferred to as a ring d, which is secured to rotate with controller-arm` a and a contacter f, which is rotatable responsively to the pivotal movements of arm b onits stud' |04,'an'd an alternating current potentiometer which includes a 'similar corewth a toroidal winding, hereinaiter `referred to asa ring d, which is fixed to bracket lr`r1' 'Jv-einent of controller-arm b relativelyto con# v'troller-arrn'b by a sprocket III fixed tovarm4 b, a

sp'ro'cket-chainv H2, and a` sprocket-wheel H0, 'whiclris'rotatable around stud H13,Y and carries -con-tactersf.1 This connection causes thefcon- `taeter f4 to rotate around ring d when controllerfarm-'b is rotated on, and relativelytto, controllerarrn a, the effect being the same as'if the ring d-werle'xed to 'the outer end of arm a and contacter f' were fixed directly to arm b. The loc'ation ofboth of the'rings d, c around stud |03, `sirnr'l-liAi-les the electrical-connections for said rings and `the'l'associa-t-ed contacters. `One end of the winding of potentiometer-ring D is connected-by :conductor: e4` to" power-'supply line-conductor 3B 4and-its other `end'is connected by conductora5 topower-supply line conductor 3L Likewise, the corresponding ends of the winding on potentioine'terring 'd are connect-ed to power-supply lineconductors '36,31 through conductors d', 30a and 112,"3 I a respectively. Potentiometer-rings D d have their Vcorresponding terminals connected across one phase of the power-supply line and areenergizedy at all times` in equal phase and voltage in such manner that correspondingV points on each yof the two rings have exactly equal potentials.

' v'The means for controlling the operations of motor B includes an alternating current polarrelay H', whichY comprises a helix 'HJ around armature il 'and connected by conductors to c'ontacters F, f; lfield-windings 68, 69 and a magnet mvfor 4holding said armature in its centralyized'position. Field-windings 69, 'Hl are energized through conductors 3l, 38, transformerwindings J,v J and conductors e4, c5,`irom"the sainefphaseof vpower-supply as the windings of potentiometer-rings D, d.

Armature 1| is movable in opposite directions 4,from its centralized position to shift either of a pair of switches l2, i3 which control a relay G which controls "circuits for operating motor B in opposite directions. Switch l2, when armature 1l is shifted in one direction, closes against a contactli to 'establish a circuit through helix 'g4 for operating'its associated switch g", which Acarries,contacts 56, 51, 58 for closing .a three# 'phase circuit through motor B' for operating the motorin one' direction. vSwitch 13'is adapted tobe closed'at contact l5 whenarmature 'H is shiftedin the opposite direction lto control acircut through winding gv3 which operates its associated switch y2, which carries contacts 59, tl), tl lfor closing a three-phase circuit' through motor B for` driving the motor in the reverse direction and correspondingly shifting the supporting-arm A. When controller-arm a and supporting-arm A and, correspondingly, contacters f,"F,` are in the` same relative angular position, no difference of' potential will exist between said contacters and no current will iiow lthrough the connecting circuit-contacter' f, conductor f', Vand v'Winding 1B, lamp'33f,and contacterv F. vThe pivoted armature 'H will then be equally attracted to each ofthe pole-piecesv energized by field-windings 68, 69, vso`that armature 'll remains in its center position by -theattraction of permanent magnet m". ,l

When controller-arm b is rotated clockwise relatively to ring contacter f will vary its angu# lar position relatively to contactor F, so that a dierence of potential will exist between kthese two points, causing current' to flow through conltacterAr f, conductor. f andwinding l0, lamp 33f and contacterF, depending upon the relation of` `thexphases between-'iield-windings 68, 69, and armature-winding'l;` armature 1l will bef'at- Vtracted by 'onefpole-pieceand repelled by" the other, moving the armature to close switch 12 atcontact 145" Current will' now flow from thepower-supply. 'conductor'` 30 `through conductor 30a, contactlll, switch 12, conductor 4l, winding g4 of Arelay G", conductor' 35, ring D, and conductors e4, c3 andl 3th This circuit will shift switch g of relay Gf and close main Vpowercontacters 56, 51, 58 and energize motorV B.

These connections arie so related thatmotor B is arranged to rotate. arm B in such 'direction as to` restore the 'equality 'of potential between contacters f, F. As soon "as-this equality of potential is 'established,ywinding l0 is no longer energized and centering magnet'm' restores armature II to its center position to open switch 12 at contact 14de-energizing said power-'relay winding g4, allowing switch g to'drop and open contacts 56, '57, 58 an'dstop motor B. 1 f..

Whenarm b is rotated inl a counter-clockwise direction` from a. position in which arrn b and arm a-'are in the same positions frelatively to potentiometer-rings'id, D,"respectively, a difference of potential is again-established between Contacterslf, F, sothatcurrent will flow through the Acircuit including contacter f, conductor f and' winding 1U, lamp 33f, 'andconductor F. At this'point,the phase relation `between the cur'- rent owing through armature-winding l! and the current flowing through'eld-windings S9, 1B, isfexactly opposite4 from the relation between these two currents which was `produced when arm b was rotated in a clockwise' direction'in relation to'arrn` B, so that armature 'Il will vbe attracted in the-direction 'to close switchv 'i3 at contact l5, thus permitting current to flow from thepower-supply conductor 32 through switch 13, contact l5, conductor 42, power-'relay winding g3 of Irelay G', attracting the armatureswitch g2 and closing power-supply contacts 59, 6l6!,'thus energizing rnotor B'.` The closing of contacts 59, 60, 6! vinterchangesthe connection of power-supply conductors 3l] and 32 in relation to the connections which existed when contacts 5t,I 51, 58 were closed, causing the motor'to rotate in the opposite directionv to rotate arm B in such direction as torestore the equality of potential betweencontacters f, F; `Thisexemplifies control'rnechanism for the motor B for swinging arm Biresponsively tothe manual shift ofcontrollerarm b, whereupon the supporting-arm will be shifted, .in direction and extent, to correspond with -the movement of said controller-arm by the operator.

'y -Inyrnoving the sandslinger to ram all portions 'of a iask, asvdesired,l it isnecessary to move the sandslinger horizontally varying distances in any direction, andback` and forth,fat the will ofi--the-,operaton.andjiforrthis purpose, it is necessarytocompound the pivotal movements of the supporting-arms? rIhe controller-arms c, b are pivotally supported so theyare simultaneously movable and so their'V movements may be compounded similarly `to v supporting-arms lto control the power-driven mechanism for corresponding compound movements `of thesupporting-armsto reproduce either the simple or compounded movements of the controller-arms. The controller-arms are -pivotally supportedfor angular 'movements `corresponding-'to the angular vmovements of the supporting-arms. When both arms are shifted in the same, or in opposite, di-

' rections, the motors for shifting the supportingare mostly always compounded to move the projector so it will traverse different paths anddearms, respectively, will be operated to effect movements of the respective supporting-arms in synchronism with, or responsive to, the vdirection and extent of the movements of the controllingarms. l u

. In operation, when the projector is to be shifted by the swinging of either or both of supporting-arms A, B, bypower, the operator will `move the handle b of the controlling-device in @whatever `direction,and according to the extent 28 he desires to move the projector and the movement' of the vcontroller-armswill, through thev controlling mechanism, control the separate or simultaneous swinging movements of supporting- J armA by motor A'Vand the swinging of support- 30" ing-armB by motor B' will be synchronizedwith, or in accordance with, the direction and l'extent of the movements of `controller-arms a, b from handleb bythe-operator.,` In other words, the

operatorv merely moves either', or both, of the controller-arms through handle b according tor` the direction and extent or path of movement desired of ther projector and the controlling mechanism controls the operation of motors A', B to effect corresponding individual Vor simul-` taneous movements of supporting arms A, B.A In practice, the movements of ythe supporting-arms liver sand into all'portionsV of the flash'and these movements are readily controlled by vcorrespondingly compounding the movements of the controller-arm. VThe movements` of the handle h in any direction or extent causes the powershifted supporting-arms I.to follow the `angular 50i"` movements of the controller-arms.

..The elements of th'econtrolling mechanism are electrically connected,.as indicated in Fig. 1f Aj series of` conductor-rings H5 areconnectedf-to rotate with shaft 96, which rotates with supporting-arm-A, and the conductors for current toand potentiometer-rings D, c, d, which-are carried by `the supDDrting-arms A, B are suitably connected to said conductor-rings.y Shaft 9B,

`which carries the contacter E, is lxed to-an arm 19a, which is iixed` to sprocketwheel 79, sosaid contacter will rotate with said sprocket, which operates supporting-arm A through cushions 82.

Shaft 99, which carries contacter F, is secured to rotate with gear 90,which shifts supporting'-arm`v B through cushions 94. By rotating'theseconl tac'ters with the driving gears 19, 90,' respectively, they control the drivinglmechanisms lto position the supporting-arms through the cushioned con-f nections.

Fi'eld-windingsfll, 6| of polar-relay I-I andj held-windings 68, 69 of relay H' are connected to the secondary'winding J of "a transformer, to4 supply a reduced voltage to' said windings., The" lprimary-L'coilJ of this `.transformer iis-connected,

. circuits.

ent is: v Y 1. The combination ,with a rotary projector for` to conductors e4, e5, which are connected'through conductors c3, e4 to line-wires 3|, 32.

'If either of the controller-arms a, b is quickly moved vto a `position considerably inadvance of the corresponding positions ofthe supportingarms A, B, respectively, an excessivev potential diiference `will be established in the circuits between the contactersof thepotentiometers. In

order to avoid overloading and possible damage l tey the armature-windings 63, lil, a device having a positive coefficient .of resistance versus tem.- perature, for example, a tungsten lamentlamp 33, is included in theline c kbetween conta-eters c; E, and a similar lamp 33h is included in the line f2, between contacters f, F. During conditions'ofno'rmal operation of the device, when only small diierences of potential exist in Ithe lines between the contacters, only small currents will flow through the positive resistance devices so that theirresistance is maintained at a very low value a-nd does not absorb any appreciable` power from the circuit, As the potential between the connected contacters of the potentiometers is sharply increased,I more current tends to ow "through the positive resistance devices, causing their temperature to rise which, in turn, increases the resistance, thereby tending to offset, or maintain constant,

v Each of the mtors A' ,and` B is usually' prfthe current flowing through the 1 vided with'a magnetic brake (not shown), as fwell movable correspondingly and proportionately to4 the desired movements of the projector. `It also` exemplifies controlling-means for themove'ment of a pair of supporting-arms Awhich are pivotally supported forlcompound movements, 'which comprises controlling-arms which are adaptedfor similar movements.v It also exemplifies electrical means for controllingfpower--driven mechanism for shifting the supporting-structure'foi" a projector to move rit over iiasks of great area.` It also j exemplies controlling-means which comprisesfa plurality of members swinging correspondingly totheswinging supporting-members Lof the sand# slingeigrwhereby the operator, `by similar or correspending movements ofthe control-members, will ,y automatically control thepower'for moving the .pivotally-connectedsupporting-meinbers.u N y 'The invention'is not to be unde'rstoodfas re'-` stricted tothedetailsset forth, sinceV these may be modified withingthe scope of the appendedy claims, Awithout departing 4from the spirit and 4 6 Havingjth'us described the invention, whatwe and desire to secure by Letters Patscope .of the invention. i

claim as new slinging sand, a pair of pivotally-connected arms for movably supporting the projector for hori- Y zontal movement in any direction, and means for"` feeding' sand to the projector, of power-driven;

mechanism forswinging each of the pivoted' sup- 75 i porting-arms, a` manually-shiftable control-defeeding sand to the projector, of electric motors for swinging the pivoted supporting-arms, a manuallyf-shiftable control-device comprising a pair of correspondingly pivotally-connected members, one of which is mounted to swing coaxially with the pivot between the supporting-members, and electrical means, controlled by the movements of saidcontrol-members, for controlling the operatic-n of the electric motors lto shift the projector, distantly and directionally, according to the l movements of the pivoted control-members.

3.' The combination with a rotary projector and a pair of pivotally-connected arms for movably supporting the projector for horizontal movement in any direction, of l.reversible power-driven mechanism for respectively shifting the pivoted supporting-membersa manually-shiftable control-device comprisinga pair 4of corresponding "pivotally-connected members, and means,l controlled by the movements of said control-members, for controlling the operation of said mechanisms to shift the projector, distantly and directionally, in response to the movements of the Y sponse to the movements of the controller-arms,

pivoted controlling memberarespectively, said means comprising a pair of potentiometers variable, respectively, by the movements of one of the supporting-members and oneof the controlmembers, and a pair of potentiometers variable by the .other supporting-member and controllingmember, respectively,`vand means controlled by the lpotentiometers for varying the direction in which the supporting-members aredriven in rerespectively. v

r4. The combination with a rotary projector and a pair of pivotally-connected arms for movably supporting 'the projectorr for horizontal movement in any direction, of reversible electric motors for respectively shifting the pivoted supporting-members, Ya manually-shiftable controldevice comprising a pair Vof pivotally-connected members, and means, controlled b-y the movements of said control-members, for controlling the operation of said motors to shift the projector,

distantly and directionally, in response to the movements of the pivoted controlling. members,

,respectively said means comprising a pair of potentiometers variable, respectively, by the movement of one of the supporting-members and one of the control-members, and a pair of potentiometers variable by the other supporting-member and controlling-member, respectively, and means controlled by the potentiometers for varying the direction in which Ythe supporting-members are driven 'in response to the movements of the controller-arms, respectively.

5. The combination with a rotary projector land a structure for supporting the projector to move horizontally in any direction, of poweroperated mechanism for shifting the structure, a

manually-shiftable control-device, and electrical means controlled'by movements of said device for controlling the operation of said mechanism to shift the projector,A distantly and directionally, in response to movements of the control-device, said means being controlled by variation of potential responsive to the movements of said device, and means for preventing overload of potential in the control-means when the control-device is shifted a considerable distance and the potential is greatly increased. ,o v

6. The combination with a rotary projector and a structure for supporting vthe projector to move horizontally in any direction, of power-operated mechanism for shifting the structure, a manually-shiftable control-device, and Aelectrical means controlled by movements of said device for controlling the operation of said mechanism to shift the projector, distantly and directionally, in response to movements of the control-device, said means comprising a pair of potentiometers, controlled by variations ofthe potential responsively to the movements of said device, and means for preventing overload of potential in the controlmeans when the control-device is shifted a con-Y siderable extent and the. potential is greatly'in.- creased.

7. The combination with a rotary projector and a structure for supportingv the projector to move horizontally in any direction,of power mechanism for shifting the structure, cushioning- *means between said mechanism and said struc-l ture, a manually-shifrtable control-device, and means controlled by the movements of said -de- Vice for controllingv the operation of saidJ mechanism to shift the projector,kdistantly and= a structure comprising a pair of pivotally connected arms for supporting the projector to move horizontally in any direction, of power-mechanisms for shifting the arms, respectively, cushioning-means between said mechanisms-and said arms, respectively, a manually-shiftable controldevice, and means controlled by the movements of said device for controlling the Aoperation of said mechanism to shift the` projector,l distantly and directionally, in response tothe movements of the control-device. i L

9. Thecombination with a rotary power-driven projector, and a structure for supporting the projector to move horizontally in any direction so the projector will ram sand in all portions of a viiask, of a manually and selectively operable control-"device shiftable in accordance with the desired movement ofv the Aprojector in all. of the directions in which the projector is movable, and power-operatedl mechanism for shifting the structure to shift the projector, controlled by the f selective Ymovement of said device to operate said mechanism to shift the projector in direction and correspondingly to the selective movements of` the control device.

10.. The combination `with a rotary powerdriven projector, and a structure for supporting the projector `to move horizontally in any direction so the projectorv willramsand in' all por` of the directions in which the projector is movable, and-power operated mechanism for shifting Ythe structure'to move the projector, con-,i

Y trolled by the selective movement of `said device? to operate said mechanism to shift the' projector Y,

in direction, 'correspondingly `to,zand a propormovements of the control device.

11. The combination with a rotary projector,l

a structure for supporting the projector to move horizontally in any direction so the'projector will ram sand in all portions of a flask, and powermeans supported by the structure for driving the projector, of power-operated mechanism vfor shifting the structurev to move the projector horizontally in any direction, a manually and selectively shiftable control device operable in accordance with the desired movements of the projector in all of the directions in which the projector is movable, and means controlled by the selective movement of said device for conshifting the structure to move the projector horizontally in any direction, a manually and selectively shiftable control device operable in accordance with the desired movements of the projector in all of the directions in which the projector is movable, and means controlled by the selective movement of said device for controlling the operation of said mechanism to shift the projector directionally and correspondingly to the selective movement of the control device, but over a greater range.

13. The combination with a rotary projector, a plurality of projector supporting members supported for separate or compound movement and power-means for driving the projector mounted on one of said members, of power-operated mechanism for shifting said members separately or simultaneously to move the projector horizontally in any direction to ram all portions of a mold, a manually and selectively shiftable control device operable correspondingly to the supportlng members, and means controlled by the selectlve movement of the control device for controlling the operation of the shifting mechanism jector mounted on one of said members, of poweroperated mechanism for' shifting said members separately or simultaneously to move the projec- .tor horizontally in any direction to ram all portions of a mold, a manually and selectively shiftable control device comprising a correspondingly plurality of members movable ,correspondingly to the supporting members, and means controlled by the selective movement of the control device for controlling the operation of the shifting mechanism to pvotally-move the supporting members singly or compoundly in angular distance and direction corresponding to the selective movements of the members of the control device.

l5. The combination with a rotary projector, a plurality of projector supporting members movab-lysupported for separate or compound movement and power-means for driving the projector mounted on one of said members, of poweroperated mechanism for shifting saidv members separately or simultaneously to movethe projector horizontally in any direction to ram all portions of a mold, a manually and selectively shiftable control device comprising a corresponding plurality of members mounted for separate or compound movement correspondingly to the `supporting members, and means controlled by the selective movement of the members of the control device for controlling the operation of the ment and power-means for driving the projector mounted on one of said members, of poweroperated mechanism for shifting said members separately or simultaneously to move the projector horizontally in any direction to ram all portions of a mold, a manually and selectively shiftable control device comprising a corresponding plurality of members pivoted for separate or compound movement corresponding to the movements of the supporting members, and means controlled -by the selective movement of the members of the control device for controlling the operation of the shifting mechanism to pivotally move the supporting `members singly or oompoundly in angular extent and direction corresponding to the selective movements of the members of the control device.

MURRAY G. CLAY. ELMER O. BEARDSLEY.

shifting mechanism to move the supporting mem- ,30 

